美制螺纹常用规格极限尺寸表

美制螺纹常用规格极限尺寸表
公称尺寸和每英寸牙数
螺纹系列代号
大径极限最小
最大
中径极限最小
最大
小径max
螺胚直径最小
最大
8-32
(0.164-32)
0.__.9903
0.__.1427
0.__.5535
0.__.6271
0.__.1699
3.58
4.074.72
5.45
6.948.409.83
3.61
4.104.75
5.48
6.988.449.87
10-24
0.__.6177 0.__.8006 0.__.0284 0.__.1123 0.__.5027 12-24 (0.216-24) 0.__.2781 0.__.4610 0.__.6863 0.__.7727 0.__.1631 1/4-20 (0.250-20) 0.__.1163 0.__.3221 0.__.4026 0.__.4966 0.__.7650 5/16-18
0.__.6860 0.__.9070 0.__.8885 0.__.9901 0.__.1747
3/8-16 (0.375-16) 0.__.2532 UNC
0.__.4920 0.__.3490 0.__.4607 0.__.5438
7/16-14 (0.4375-14) 0.__.8153 0.__.0769 0.__.7790 0.__.8984 0.__.8519
1/2-13
(0.50-13)
0.__.3850
0.__.6619
0.__.2649
0.__.3919
0.__.2641
11.3411.3812.8012.8414.2714.3217.2817.3320.2720.3223.2223.2 7
9/16-12
(0.5625-12)
0.__.9573
0.__.2469
0.__.7406
0.__.8727
0.__.6510
5/8-11
(0.625-11)
0.__.5270
0.__.8344
0.__.3358 0.__.0023 3/4-10 (0.750-10) 0.__.6766 0.__.0043 0.__.2034 0.__.3533 0.__.8877 7/8-9 (0.875-9) 0.__.8237 0.__.1767 0.__.1828 0.__.3429 0.__.7147 1“-8 (1.000-8) 0.__.9682 0.__.3492
0.__.2867
0.__.4528
1.螺胚直径指滚丝前的尺寸，数值为依经验公式计算而得，在实践中需验证。

2.标记示例：10-24UNC-2A(或0.190-24UNC-2A)、3/8-16UNC-2A(或0.375-16UNC-2A)
（注：表中上行斜体数值单位为英寸，下行为毫米）
公称尺寸和每英寸牙数
螺纹系列代号
大径极限最小
最大
中径极限最小
最大
小径max
螺胚直径最小
最大
8-36
(0.164-36)
0.__.0056
0.__.1453
0.__.6170
0.__.2791
3.65
4.244.82
5.697.178.7510.1911.7813.2714.8517.9120.9323.90
3.67
4.274.85
5.717.208.7810.2311.8213.3114.8917.9520.9723.95
10-32
(0.190-32)
0.__.6507
0.__.8031
0.__.2113
0.__.2875
0.__.8303
12-28
(0.216-28)
0.__.2959
0.__.4610
0.__.7904
0.__.8717
0.__.3485
1/4-28
0.__.1595 0.__.3246 0.__.6515 0.__.7353 0.__.2121
5/16-24 (0.3175-24) 0.__.7267 0.__.9096 0.__.1272 0.__.2212 0.__.6116
3/8-24 (0.375-24) 0.__.3142 UNF
0.__.4971 0.__.7122 0.__.8087 0.__.1991
(0.4375-20) 0.__.8737 0.__.0795 0.__.1473 0.__.2540 0.__.5225
1/2-20 (0.50-20) 0.__.4612 0.__.6670 0.__.7323 0.__.8415 0.__.1100
9/16-18 (0.5625-18) 0.__.0310 0.__.2519 0.__.2207 0.__.3350 0.__.5197
(0.625-18) 0.__.6185 0.__.8394 0.__.8031 0.__.9225 0.__.1072 3/4-16 (0.750-16) 0.__.7731 0.__.0119 0.__.8537 0.__.9807 0.__.0637 7/8-14 (0.875-14) 0.__.9227 0.__.1844 0.__.8686 0.__.0058 0.__.9593
1"-12
(1.000-12)
0.__.0647
0.__.3543
0.__.8303
0.__.9801
0.__.7584
1.螺胚直径指滚丝前的尺寸，数值为依经验公式计算而得，在实践中需验证。

2.标记示例：10-32UNF-2A(或0.190-32UNF-2A)、3/8-24UNF-2A(或0.375-24UNF-2A)
公称尺寸和每英寸牙数
螺纹系列代号
小径极限最小
最大
中径极限最小
最大
大径min
底孔直径最小
最大
8-32
(0.164-32)
0.__.5306
0.__.6500
0.__.7465
0.__.1656
3.403.75
4.40
5.05
6.45
7.859.2022
年.6512.0513.4516.4019.3022.10
3.503.90
4.55
5.20
6.608.009.4010.9012.3013.7016.7019.6022.40
10-24
(0.190-24)
0.__.6830
0.__.9624
0.__.1377
0.__.2469
0.__.8260
12-24
(0.216-24)
0.__.3434
0.__.5974
0.__.7981
0.__.4864
1/4-20 (0.250-20) 0.__.9784 0.__.2578 0.__.5245 0.__.6490 0.__.3500
5/16-18 (0.3175-18) 0.__.4008 0.__.7310 0.__.0206 0.__.1552 0.__.9375
3/8-16 (0.375-16) 0.__.7978 UNC
0.__.1534
0.__.6385
0.__.5250
7/16-14
(0.4375-14)
0.__.1440
0.__.5504
0.__.9339
0.__.0889
0.__.1125
1/2-13
(0.50-13)
0.__.5918
0.__.0236
0.__.4300
0.__.5951
0.__.7000
9/16-12
(0.5625-12)
0.472022年.9888 0.__.4460
0.__.0861
0.__.2875
5/8-11
(0.625-11)
0.__.3858
0.__.8684
0.__.3764
0.__.5593
0.__.8750
3/4-10
(0.750-10)
0.642022年.3068 0.__.8402
0.__.3990
0.__.5946
0.__.0500
7/8-9
(0.875-9)
0.__.1770
0.__.7612
0.__.5994
0.__.2250
1"-8
(1.000-8)
0.__.9710
0.__.6060
0.__.3375
0.__.5610
1.000025.4000
1.底孔直径指攻丝前钻孔直径，铸铁、黄铜等较软料取小值，钢、青铜等较硬料取大值。

2.标记示例：10-24UNC-2B(或0.190-24UNC-2B)、3/8-16UNC-2B(或0.375-16UNC-2B)
公称尺寸和每英寸牙数
螺纹系列代号
小径极限最小
最大
中径极限最小
最大
大径min
底孔直径最小
最大
8-36
(0.164-36)
0.__.4036
0.__.6068
0.__.7084
0.__.7998
0.__.1656
3.45
4.004.55
5.40
6.858.459.85 3.674.274.855.71
7.20
8.7810.23 10-32
(0.190-32)
0.__.9624
0.__.1656
0.__.3104
0.__.4094
0.__.8260
12-28
(0.216-28)
0.__.4958
0.__.7244
0.__.0038
0.__.4864
1/4-28
(0.250-28)
0.__.3594
0.22022年.5880 0.__.7607
0.__.8699
0.__.3500
5/16-24
(0.3175-24)
0.__.7818
0.__.0358
0.__.2492
0.__.3711
0.__.9375
3/8-24
(0.375-24)
0.__.3820
UNF
0.__.8367
0.__.9611
0.__.5250
7/16-20
(0.4375-20)
0.__.7282
0.__.0330
0.__.2870
0.__.4242
0.__.1125
1/2-20
(0.50-20)
0.__.3284
0.__.6078
0.__.8745
0.__.0167
0.__.7000
11.4011.8212.8513.3114.4514.8917.4017.9520.3520.9723.9023.9 5
9/16-18
(0.5625-18)
0.502022年.7508 0.__.0810
0.__.3706
0.__.5204
0.__.2875
5/8-18
(0.625-18)
0.__.3510
0.__.6812
0.__.9581
0.__.1105
0.__.8750
3/4-16
(0.750-16)
0.682022年.3228 0.__.6784
0.__.0188
0.__.1839
0.__.0500
7/8-14
(0.875-14)
0.__.2692
0.__.6756
0.__.0464
0.__.2242
0.__.2250
1"-12
(1.000-12)
0.__.1140
0.__.5712
0.__.0259
0.__.2189
1.000025.4000
1.底孔直径指攻丝前钻孔直径，铸铁、黄铜等较软料取小值，钢、青铜等较硬料取大值。

2.标记示例：10-32UNF-2B(或0.190-32UNF-2B)、3/8-24UNF-2B(或0.375-24UNF-2B)。